Salmon aquaculture or farming is a global intensive commercial industry worth billions of pounds per annum, salmon and trout farming was overall worth US$10.7 Billion in 2007 (FAO 2011).
Why farm salmon?
Salmon are considered the “Super Chicken” of the sea (Torrissen et al. 2011). Not only do they grow extremely fast but they are extremely efficient to raise compared to more conventional farmed animals give yields of 80-90% of the energy that is put in them. By way of comparison 100 kg of dry feed will produce 65 kg of salmon compared to only 20 kg of chicken and 15 kg of pork.
Sea fish in general are extremely healthy to eat due to the oils they contain, reducing the risk of heart disease in the first place and has a positive effect of existing heart disease.
A number of salmoid species are used in the industry but by far and away the most important species is the Atlantic Salmon (Salmo salar) which is native to the north Atlantic. This species is raised on a commercial scale in both its natural range in countries such as Norway and Scotland but they are also farmed far outside their natural range in Chile and Western North America.
The Farming process
Salmon are typically farmed in two stages, firstly in a freshwater hatchery and then in a seawater cage. The freshwater stage involves spawning, egg production, hatching and the early feeding stages. As the young fry grow bigger they becoming fingerlings and the finally smolts, at this point they are adapted to seawater, this process takes 12-20 months. At this stage the smolts are transferred to marine cages and raised to market size and value which is typically 3-5 kg.
Norway is the largest producer at present, responsible for 33 % of production, Chile 31%, and other European producers including Scotland contributing 19%.
There is a great deal of controversy around the ecological and health impacts of intensive salmon aquaculture as well as its long term sustainability. There are particular concerns about the impacts on wild salmon and other marine life. The rapidly growth and evolution of the salmon aquaculture industry especially in poorer countries is of particular concern, were strict regulations are not in place to control the industry to keep it viable and problem free. To explore the concerns and state of Atlantic Salmon aquaculture around the world this website deals with three main case studies: Feeding the Salmon in Scotland; Environmental impacts in Norway; and the Impacts of Diseases and Parasites in Chile.
FAO (2013). Cultured Aquatic Species Information Programme: Salmo salar. http://www.fao.org/fishery/culturedspecies/Salmo_salar/en
Marine Harvest (2012). Salmon Farming Industry Handbook 2012. http://www.marineharvest.com
Torrissen et al. (2011): Atlantic Salmon (Salmo salar): The “Super-Chicken” of the Sea?, Reviews in Fisheries Science,19, 257-278.